package com.wpw.dream.map;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MapTest {
	public static void main(String[] args) throws InterruptedException {
		Map<String, String> map = new HashMap<String, String>();
		
		for (int i = 0; i < 18; i++) {
			map.put(i + "", i + "");
			System.out.println(map.size());
		}
	}
	public void inspect(List<Object> list) {
		for (Object obj : list) {
		System.out.println(obj);
		}
		list.add(1); //这个操作在当前方法的上下文是合法的。
	}
	
	public void add(List<?> list) {
		list.add(null);
		Object object = list.get(1);
	}
	
	public void add2(List<? extends Number> list) {
		
	}
	
	public void Test() {
		List<Number> list = new ArrayList<>();
		add2(list);
	}
	

}
